Filling Floor Heater Hole so I can lay Carpet.

I removed a large floor heater from my home that was built in the 40s. The heater it out and I need to frame it to hold a few pieces of plywood so the floor will be even and sturdy for people to walk on. What is the best approach for this. Thanks.

Filling Floor Heater Hole so I can lay Carpet.

Filling Floor Heater Hole so I can lay Carpet.

I would assume that the floor joist(s) that were interrupted have headers to close off and square the opening. In that case I would bolt or screw a ledger to the sides of the opening and run a short joist or two across the opening and place my plywood patch on top. I would install the joist(s) in metal hangers. Make your ledger and short joists the same height as the existing floor joists. Make you floor patch the same thickness as the existing floor. Some construction adhesive on the backs of the ledgers is a good idea as well as gluing down your flooring patch.

Filling Floor Heater Hole so I can lay Carpet.

From your picture, I would install 3 short joists from "brace to Brace". The ones along the edges, I would place so that they support the esxisting floor as well as your new patch. Then I would fill in along the "braces" with 2x4 to stiffen up your patch. Since this hole has been there since the 1940s, I would assume that it isn't going to sag anymore than it already has. Some construction adhesive is a good idea. Metal joist hangers to connect your new joists to the "braces" is a good idea as well. Make your new joists the same height as the originals. Make your floor patch thickness the same as the original floor.